European privacy authorities have invited Google, Microsoft and Yahoo to discuss the implementation of a landmark ruling by Europe's top court that gives people the right to have personal information excluded from search results.

The main search engine providers in Europe were invited to attend a collective consultation meeting about the ruling with the Article 29 Working Party (A29WP), which brings together data protection authorities from across the EU, according to a spokeswoman for the European Data Protection Supervisor (EDPS), which is part of the working party.

They will meet next Thursday in Brussels, added a spokeswoman for France's data protection authority CNIL, the National Commission on Informatics and Liberty, which currently presides over the group of data protection authorities.

A Microsoft spokesman said the company has received the invitation and is happy to attend, while Google said it would cooperate with privacy authorities. Yahoo did not immediately return a request for comment.

Under the May ruling by the Court of Justice of the European Union, search engines can be compelled upon request to remove results in Europe for queries that include a person's name, if the results shown are" inadequate, irrelevant or no longer relevant, or excessive."

Since than, Google has received over 70,000 take-down requests covering more than 250,000 Web pages. It also started adding a warning to some search results on its European sites, saying some results may have been removed under European data protection law, and it also started telling Web masters which links to content on their website were removed.

So far, the ruling has already caused a heated debate about which results should and shouldn't be blocked by the search engines. In deciding which results to remove, search engines also have to keep in mind the public interest, which, as Google's chief legal officer David Drummond said last week, makes the removal tests "very vague and subjective."

Some links to British news articles, for example, were erroneously removed, and have since been reinstated by Google.

Meanwhile, data protection authorities are concerned about the implementation of the ruling by search engines. One point of concern is Google's practice to erase search results from their European domains, while it keeps showing the results on its .com domain. Google justifies this practice by arguing that the .com domain is not targeted at European users.

However, this a problem that clearly puts the effectiveness of the entire decision in question, CNIL's director of technology and innovation, Gwendal Le Grand, told the Wall Street Journal. The data protection regulators also plan to discuss with Google the way it has been sending notifications, the newspaper reported.

Meanwhile, the A29WP is working on guidelines to develop a common approach of EU data protection authorities on the implementation of the ruling, the EDPS spokeswoman said.

These guidelines are scheduled to be adopted in the autumn and aim to help data protection authorities build a coordinated response to complaints from people when search engines do not erase their content upon request, she said.

Loek is Amsterdam Correspondent and covers online privacy, intellectual property, open-source and online payment issues for the IDG News Service. Follow him on Twitter at @loekessers or email tips and comments to loek_essers@idg.com